Coaxial connector



2 Sheets-Sheet 1 Filed Sept. 11, 1963 R m m m April 5, 1966 e. w.ZIEGLER, JR

COAXIAL CONNECTOR 2 Sheets-Sheet z Filed Sept. 11, 1965 NONWHL CABLE S mw M U G C H %M m D. .L E u 3 R N DE F. NV T U0 OVEQSlZE CABLE OPUNDERSQE RlNG R 3 m L 6 E l 1 W CL G E O E 6 Z 7 H T G N E L Cu m DR 6\Nr K c O L United States Patent 3,245,027 COAXIAL CONNECTOR George W.Ziegler, Jr., Carlisle, Pa., assignor to AMP Incorporated, Harrisburg,Pa. Filed Sept. 11, 1963, Ser. No. 308,265 9 Claims. (Cl. 339-89) Thepresent invention relates to an improved coaxial connector of the typeutilized to provide a low-loss path for a broad range of signalfrequencies.

As is well understood, the basic purpose of an electrical connector isto provide a mechanical and electrical interconnection of electricalsignal paths. With respect to power applications wherein the electricalsignals are either DC. or low-frequency A.C. current carrying nointelligence content, design requirements are met by providing amechanical interconnection which is easily and quickly accomplished andan electrical interconnection which is of low resistance and is stablein the presence of the particular environmental use for which theconnector is designed. I

The continuing expansion of the use of the so-called radio frequencysignals has raised further criteria which must be met by connectorscapable of handling the higher frequencies. Among these are therequirements that the connector not introduce distortion into the signalpath such that the intelligence content of the signal is alteredappreciably. A further requirement is that the connector havecharacteristics such that signal losses are minimized. A standardmeasurement of whether or not a given connector meets this latterrequirement is the VSWR test. If a connector has a relatively low flatVSWR over the total frequency range through which the connector isdesigned to operate, then it may be considered as satisfactory,electrically.

A standard test as to whether or not a given connector meets mechanicalcriteria is the pull test wherein the connector is secured to cable andsubjected to tensional loading to the point of destruction of eitherconnector or cable. If the connector maintains satisfactory electricalcharacteristics and does not pull apart or cause the cable to pull apartat some point below the nominal rated force required for cable breakage,there is a strong indication that the connector is mechanicallysatisfactory.

In efforts to meet the requirements for mechanical strength, the priorart has most often turned to relatively bulky and complicatedinterminating parts which require a considerable amount of assembly timeand special preparation of the cable to which the connector is attached.As a direct result of this practice, electrical requirements have eitherbeen neglected or compromised.

It is one object of the present invention to provide a coaxial connectorhaving superior electrical characteristics over a broad range of signalfrequencies and at the same time provide a connector having featurespermitting the rapid installation of connector parts to achieve amechanical interconnection exceeding the nominal pull strength of thecable to which the connector is attached.

It is a further object of the invention to provide a simple andinexpensive coaxial connector having a relatively low VSWR over a broadrange of signal frequencies.

It is another object of the invention to provide an improved coaxialconnector construction capable of being employed without specialadditional adaptor sections, but readily mateable with adaptors if suchis desired.

It is yet another object of the invention to provide a novel means ofsecuring connector parts to coaxial cable wherein the connection withthe cable is assured despite considerable tolerance deviations in thecable or in the connector parts.

Other objects and attainments of the present invention will becomeapparent to those skilled in the art upon a reading of the followingdetailed description when taken in conjunction with the drawings inwhich there are shown and described illustrative embodiments of theinvention; it is to be understood, however, that these embodiments arenot intended to be exhaustive nor limiting of the invention, but aregiven for purposes of illustration in order that others skilled in theart may fully understand the invention and the principles thereof andthe manner of applying it in practical use so that they may modify it invarious forms, each as may be best suited to the conditions of aparticular use.

In the drawings:

FIGURE 1 is a perspective view of an embodiment of the connectorassembly of the invention secured to the ends of coaxial cable andintermated to provide a contin uous transmission path between cablehalves;

FIGURE 2 is an exploded and partially sectioned view of the connector ofFIGURE 1, showing the details of each connector half;

FIGURE 3 is a longitudinal section of the assembly of FIGURE 1 takenalong lines 3--3;

FIGURE 4 is a schematic diagram showing the novel clamping sleeveconstruction of the assembly of the inven tion before and after use interminating the cable with a connector half;

FIGURE 4a is an end-on view of the sleeve of FIGURE FIGURE 5 is aschematic diagram showing approximately, exemplary stress conditionspresent in the novel locking sleeve of the invention in use; and

FIGURES 6 and 7 are longitudinal sections of further embodiments of theinvention.

The foregoing objects are attained in the present invention through thecombination of a novel locking sleeve securing each 'half of a coaxialconnector to the cable to be connected and, additionally, improvedconstruction and arrangement of conductor contact membersto providesuperior electrical characteristics. The improved construction furtherpermits attachment of terminal portions of the connector directly to thecable in a manner whereby no additional adaptor sections are necessary,and where tolerance deviations of both cable and connector parts areinherently accommodated.

Referring now to the characteristics of typical cable served by theinvention, FIGURE 1 shows an interconnection wherein separate halves ofa coaxial cable 16) are mechanically and electrically joined by aconnector 18 to provide a signal path between electrical or electroniccomponents. Cable 10 includes an outer conductor 12 and a coaxiallyspaced center conductor 14 separated by a dielectric 16. Cable of thistype is manufactured in ranges of from one eighth to three and one halfinches in outer diameter for a Wide variety of uses in handling signalsranging from DZC. up to ranges overlapping with wave guide frequencies.Typically such cables are found linking components in radar, televisionand radio communication equipment, wherein signal frequencies range froma few thousand kilocycles up to and above ten thousand megacycles.Cables for such use come in a variety of constructions including that of10 having a solid outer conductor formed of aluminum tubing with a solidinner conductor formed of copper rod surrounded and held by a foamedpolyethylene dielectric, or a construction wherein the center conductoris a solid copper rod surrounded by nylon beneath an outer conductor ofmetallic woven braid. Other cable constructions include inner and outerconductors similar to that shown with the dielectric therebetween beingformed by air and a thin spiral Teflon ribbon adapted to support thecenter conductor. Yet other cable forms include transversely orientedthin discs of ment of the invention includes a center conductor of solidcopper rod approximately 243 thousandths of an inch in diameter, atubular aluminum sleeve forming the outer conductor and a solid foamedpolyethylene dielectric sleeve disposed therebetween. The aluminumtubing is approximately 37 thousandths of an inch in thickness and hasan outer diameter of approximately 750 thousandths of an inch. Thefoamed polyethylene dielectric sleeve has an approximate dielectricconstant of K=1.5.

Interconnection of cables of the above mentioned types has heretoforeproven to be a difficult task and the prior art has evolved about aconnector construction wherein the cable outer conductor must beexternally threaded or gripped by serrated surfaces for each conductorhalf with a number of connector parts thereafter threaded onto the cableand fitted to separate intermating adaptor sections. This approachrequires that the cable be stripped with a portion of the centralconductor left protruding for attachment with the connector partsaccommodating the central conductor connection. Due to the complexitiesof the mechanical interconnection achieved by following this approach,various compensating adaptor sections have necessarily been introducedin an attempt to match the connector to the cable with respect tocharacteristic impedance Nevertheless since fiat compensation can onlybe accomplished at a given frequency the connectors made in accordancewith the prior art have not provided a particularly satisfactory VSWRover a broad range of signal frequencies The connector of the inventioneliminates the need for compensation as well as simplifying cablepreparation and assembly of connector halves thereon Interconnectingcables is the connector assembly of the invention 18 comprised of halves20 and 80 adapted to be intermated for completion of the electricalpaths formed by the outer conductor shell 12 and the inner conductorshell 14 As shown in FIGURES 2 and 3 half 20 includes female portionsadapted to cooperate with male portions of half 80 to form such paths Aswill be further apparent from FIGURES 2 and 3, the outer end portions ofhalves 20 and 80 are electrically and mechanically identical with theinner and mating portions being similar but modified to an extent topermit mechanical engagement.

In connector half 20, there is included a five piece assembly comprisedof a central metallic sleeve 22, an intermating metallic sleeve 44fitted thereover, a metallic locking sleeve or ring 72, a central,coaxially disposed contact metallic plug 60, and a tubular dielectricinsert 56. Half 80 is comprised of a four piece assembly including ametallic sleeve 82, a metallic locking ring 110, a central contact plug98, and a tubular dielectric insert 96. Assembly 18 includes anadditional piece in the form of a resilient seal 78 adapted to be fittedin between the connector halves 20 and 80. The ten pieces formingassembly 18 compares with twenty or more pieces of connectors of theprior art having a similar function.

Referring now to FIGURES 2 and 3 and to half 20 in more detail, thecentral sleeve 22 is an integrally formed shell having a relatively thinsleeve extension 24 tapered as at 28 and a forward and thicker portion30 joining 24 at a radially disposed transverse face 32. Portion 30further includes as an integral extension a radially ex tending flange34 abutting 30 to define a transverse face 36 and a forward transverseface 40. Sleeve 22 includes two longitudinal bores 26 and 42 each of aconstant diameter. Bore 26 extends through portion 30 and sleeveextension 24, and is of a diameter approximating D, the inner diameterof cable conductor 12 such that the maximum deviation of cable andsleeve tolerance will still permit the insertion of the cable dielectric16 within the bore. Bore 42 extends for a very short portion withinportion 34 to provide a cylindrical surface adapted to intermate andengage a corresponding portion of connector half fitted therein, tomaintain axial alignment of the connector halves.

Fitted over the outside of 22 is sleeve 44 having a rear portion 50 withan internal rim 51 adapted to lock against face 36 of 34 to limit axialmovement of 44 from end 22. Sleeve 44 further includes an internal bore52 threaded as indicated to cooperate with complementary threading onhalf 80. At the end of the threading of bore 52 is a smooth portionprovided to cooperate with the outer surface of 34 and a further bore 55adapted to fit over the outside surface of section 30. Overlying portion50 of sleeve 44 are fiats 45, better shown in FIGURE 1, adapted toprovide a gripping surface for forced rotation of 44 during connectorassembly.

The central plug or contact pin member 60 includes an end portion 62 ofreduced diameter threaded about its periphery as at 64, and adapted tofit within a complementary threading formed in the end of conductor 14.The outer diameter of 60 is d, that of conductor 14. In practiceconductor 14 is first drilled, then tapped and threaded to a depth suchthat 60 may be threaded therein with the surface 61 thereof drawn snuglyagainst the end face of the conductor 14. The forward portion of 60 iscomprised of four resilient spring finger members 66. Finger members 66are formed by a bore provided in the end of 6t) with symmetricallyplaced slots 68 made through the outside wall thereof. The springmembers formed thereby are preferably maintained as thin as is possiblewith the fingers having a substantial spring action. The purpose of thiswill be explained more fully hereinafter.

As a further part of half 26, the locking sleeve or ring 72 is adaptedto be fitted over the outside of conductor 12 of cable 10 tointerconnect the cable with the connector half through a permanentresidual stress achieved between cable and ring. Ring 72 is of a lengthto extend over extension 24 to provide additional support against cableloads being imparted to the connector parts.

As a most important point, ring 72 is formed of a tapered shell havingone end of an internal diameter very slightly larger than the longesttolerable outer diameter of the cable and the other end slightly largerthan the largest tolerable outer diameter of extension 24 plus twice themaximum thickness of the material of conductor 12. Because of this theabove-mentioned stress is achieved to lock half 20 to the cable. Thefeatures and operation of ring 72 will be described more completely inthe description of connector assembly hereinafter to follow as relatedto FIGURES 4 and 5.

The dielectric insert includes an interior bore 58 of constant diameterlarger than the exterior diameter of pin 60, such as to provide an airspace between theouter surface of 60 and the inner surface of thedielectric. Insert 56 is preferably wedge-fitted within bore 26 underportion 30 of 22 to define an outer diameter equal to D. The length ofinsert 56 is such that the outside end is flush with the face definedbetween bores 42 and 26 and the inside end is disposed immediately underface 32. When assembled, half 20 is arranged such that the dielectric 16of cable 10 abuts the end face of insert 56.

Turning now to the complementary connector half 80, sleeve 82 isrelieved to define a face and extending axially therefrom, a portion 92having an externally threaded portion 93 adapted to fit within theinternal threading of sleeve 44. The forward end of 82 includes atransverse surface 94 complementary to face 40 of half 20. Extendingbeyond surface 94 and of a lesser outer diameter, is a sleeve extension95, adapted to fit within bore 42 against bore face 40 of half 20. Thetransverse face of the sleeve extension 95 is adapted to be disposedopposite to a corresponding face between bores 42 and 26 of half 20.Flats 83, as shown in FIGURE 1, are

the cable.

. included on the outer surface o'f'82, serve to permit half sion 86,having a bore 84 extending the full length thereof and of constantdiameter slightly larger, than the diameter D of cable dielectric 16.The centrally disposed contact pin or plug member 98 includes anextension 100 threaded as at 102 to fit within conductor 14, suit-- ablydrill tapped and threaded to receive 100 as in the manner heretoforedescribed. Pin 98 includes a -portion 104 of the diameter D extendingforwardly and a portion 106 of reduced diameter having a tapered end 108adapted to fit within the spring fingers 66 of 60. The diameter ofportion 106 is made such as to provide a frictional fit within fingers66 to accomplish a stable electrical innerface therewith. The provisionof a sliding engagement readily accommodates any slight differences inconnector parts due to manufacturing tolerances and due to differentialthermal expansion of inner and outer conductor materials.

The dielectric insert 96in bore 84 of half 80 extends along the lengthof the bore from a portion wherein sleeve extension 86 joins the body of82 to the opposite end thereof. Insert 96 has an outer diameter D andincludes a bore 97 of a diameter considerably larger than the diameterof section 104 of pin 98. The dielectric insert is wedged within bore84.

The locking ring 116 of half 80 is similar in construction to ring 72described with respect to half and operates to secure half '80 to thecable in the same manner.

The connector halves 20 and 80, after being attached to the cable in themanner to be hereinafter described, appear generally as shown in FIGURE2. The interconnection of the halves may be accomplished by merelyinserting the forward end of '80 into the forward end of 26, whereby thepin portion 108 is fitted within spring fingers 66 of pin 60, which tendto align and hold half 28 while sleeve 44 is rotated to thread over thethreading of 88 and thereafter during use. As the final turns are made,seal '78. is caught betweenfaces 40 and 94 of the connector halves,respectively and deformed, in compression to provide a seal of theconnector against environment. The positioning of 78 is su'chastoprovide sealing against entry of moisture and/ or corrosive gases atthe only possible point of entry other than through the cable or aroundthe connector locking rings 72 and 110. Additionally, if desired, .theconnector construction permits use with gas filled cable, in whichevent, seal 78 operates to contain the gas.

Thus the construction of the connector of the invention provides asingle seal in place of prior art uses of four to six seals toaccomplish the same function.

Considering further the installation of the connector of the inventionwith respect to the assembly of half 20, FIGURES 4, 4a and 5 show animportant aspect of the operation of the locking sleeve fitted over theoutside of Preparatory to installation the cable should be cut in aplane transverse to the longitudinal axis of the cable with some carebeing taken to provide a flat, even surface. The use of a fine hacksawbladeis adequate when employed with reasonable care. It is to 'be .notedthat no stripping procedure is required asin the manner of the priorart, wherein separate portions of inner conductor -14, dielectric 16 andouter conductor 12 'must be separately cut to different lengths.Afterthe initial cutting step, the center conductor may-be drilled'andtapped by any suitable means to a length as indicated in FIG- URE 3,su'fficient to receive the threading of portion 62 of central pin 60.Thereafter, the connector portion 22 may be forced into position byinserting sleeve 24-between theOD. of dielectric 16andthe ID. of outerconductor 12. The provision of a tapered edge 28 at the end of sleeve 24greatly facilitates this insertion. A taper of approximately 30 "hasbeen found satisfactory for this purpose. At the same time sleeve 24 iswedged within M6 the cable, ring 72 is held in position and therebyformed by :being partially expanded to lock the connector to cable 10.As shown in FIGURES 4 and 4a, the preassembled configuration of ring 72is that of a smooth taper extending from a larger ID. at one end to asmaller ID. at the other end. The larger ID. is made to be slightlysmaller than the CD. of portion 30, and is made 1 slightly larger thanthe CD. of the cable plus twice the thickness of 12. It has been founduseful to provide a difference in material thickness along the length ofring 72 With the thinnest portion at the larger diameter and thethickest portion at the zone of maximum stress.

FIGURE 5 shows a length stress diagram of ring 72 as fitted in positionon the connector assembly. The abscissa of FIGURE 5 represents thelength of ring 72 and the ordinate represents the stresses existing inthe ring along given lengths. By providing the taper above described,the ring 72 is stressed such that in the left portion 76 there is agradual increase of stress from approximately zero up to a maximum'inthe 'zone wherein the ri'ng'overlies the end 28 of 24 with a suddenreduction to substantially zero stress for the remainder 74 of the ringlength.

, The particular stress pattern existent in the sleeve series two usefulpurposes, the first of which is that regardless of tolerance variationin either the CD. of the cable or in the ID. of ring 72 of'theconnectorassembly there will exist, at some point along the ring, astress condition absolutely securing the connector to the cable. Byassuring that the stress condition occurs in the central area asindicated in FIGURE 5, overside cable or undersize ring conditions asshown by curve A will nevertheless provide a connection between cableand connector far in excess of that required. A condition of undersizecable or oversize ring within standard manufacturing tolerances willproduce a stress condition as shown in curve B, still far in'excess ofthatnecessary to adequately connect the connector of the cable. Asfurther indicated from FIGURE 5, the stress curves A and B will permitdestructive pull test greaterthan that of the cable. This same advantageWorks with deviations of diameter in sleeve 24.

As indicated in FIGURE 4, the central .portion of the ring 72 is tightlystressed against the cableouter'conductor overlying the end 28 of thesleeve 24. It has been found as a second advantage that in the processof assembling the connector, theparticular configuration shown providesan excellent inner-face between the sleeve 24 outer surface and that ofthe connector cable with respect to electrical continuity. It is thoughtthat actual cold welding occurs due to the contact of surfaces whereinthe surface of oxidation .products has been broken. The connectionbetween sleeve extension and cable has been found to be so tight as toforce the cable to fail mechanically before relative slippage will occurresponsive to cable torque.

An important aspect of the connector assembly of the invention is theelectrical characteristics wherein the connector is enabled to pass awide range of signal frequencies with minimum distortion, signalreflection and other loss-causing phenomena. This is achieved in the embodiment of FIGURES l3 by maintaining the characteristic impedance atany incremental length throughout the connector from end 28 to end 88,substantially that of the characteristic impedance of the cable to beconnected. In'the sectional length between end 28 and the end of thecable dielectric within the connector half 20, the distance between theouter surface of the inner conductor 14 and the inner surface of'thebore 26 of the connector is constant. The provision of the tapered end28 in conjunction with the operation in assembling the device assurethat'no substantial air gap will be present to cause an unwanteddiscontinuity at such point. The characteristic impedance meausred fromthe end of the cable dielectric to'the end of the dielectric 56 is madeto be equal to the characteristic impedance of the line. This isfacilitated by maintaining the outer surface of end 60 of the samediameter as that of the central conductor 14. The space between theouter surface of pin 66 and the inner surface of 32 is also of the samediameter as that of the preceding length of cable. The combineddielectric constant of the air spaces surrounding 60 and the insert 56is made to equal that of the preceding dielectric material of the cableof an appropriate choice of the dielectric material used for 56.Continuing on through the connector, the same spacing is maintainedbetween the outer surface of pin 98 and the inner surface of 82 as thatof the preceding sections and that of the cable. The combination of theair space about pin 98 and the dielectric material 96 is made such as toprovide a characteristic impedance equal to that of the cable and thepreceding section. Finally the characteristic impedance of the sectionfrom the end of cable in half 89 extending out beyond the end of ring110 is the same as the characteristic impedance of the line. v

In the foregoing description a preferred embodiment of the invention hasbeen described with respect to connector halves directly engageable. AsFIGURE 1 indicates, no separate interposed adaptor sections arenecessary in applications wherein the requirement is one of joining twosimilar coaxial cables. It is contemplated that the connectorassemblies, as shown, may be utilized with adaptors if such is required.For example, certain applications dictate that cable of the type shownin FIG- URE 1 be terminated into equipment through type N or type BNCconnectors having cha-racteristics in accordance with militaryspecifications. Alternatively, it may be desirable to interconnect acable of a given size through type N or type BNC connectors, into acable of the type shown in FIGURE .1. In either event, the appropriatehalf, such as 20 or 80, may be utilized in conjunction with an adaptorincluding at one end the type N or BNC structure and, as an integralpart, an intermating assembly adapted to fit with the connector half ofthe invention. For example, the structure 80, as shown in FIGURES 1-3,might be modified to include at the opposite end portions receiving themale part, a type N or BNC connector interconnected to other sizes ofcables. 'Ihis assembly could then be fitted into half 20. As a furtherexample, a cable such as interconnected to a half such as 80 might beintermated to a connector having a type N or BNC forward portion, with arear portion similar to adapted to intermate with the half 80. Thesimplicity and arrangement of the outer and particularly the innerconductive path portions of the connector assembly of the inventionmakes this possible. As an important advantage relative to the above,the provision of a threaded center contact pin member permits aconversion of the assembly to intermate with adaptors with only thecenter contact being replaced and the remaining portions used direclywithout requiring the cable to be severed and re-terminated. In such usethe center contact member is removed and replaced by a center cont-actmember of greater length suitable to accommodate the length of theadaptor section.

Turning now to an alternative embodiment of the invention, FIGURES 6 and7 show assemblies for interconnecting cables such as 10 with the outerconductive shell 12 of the cable removed, and with only the centercontact pins included, the remainder of the connector assemblies beingas shown in FIGURE 3.

The alternative embodiment shown in FIGURE 6 may be found preferable inapplications for the smaller cable sizes, as for example those having anCD. of one-half inch. The assembly of FIGURE 6 differs from that abovedescribed in that the central conductor 14 of each cable half is leftextending from the dielectric 16 as the cable is prepared for assembly.The extending portion is thereafter machined to a smaller O.D., as at 15with a series of threads thereabout adapted to cooperate with internal Ou threading as at 121 and 123 formed on contact pin members and 122. Theforward and engaging portions of the contact pins are as heretoforedescribed with respect to the pin members 60 and 98 detailed withrespect to FIGURE 3.

In the embodiment shown in FIGURE 7, the forward end of the centralconductor 14 is prepared as in the embodiment in FIGURE 6, with areduced diameter and a forward extending portion as at 15 adapted to befitted within an aperture such as or in the associated pin member suchas in 124 and in 126. A preferred method of doing this constitutesproviding a bore line 125 in the end of each contact memberapproximately the same diameter as the forwarding extending portion 15of the cable center conductor with an outside preformed pin diameter,forming a bulge as at 127 as shown by the dotted lines, which isdeformed inwardly, as by crimping or welding to secure each pin to eachconductor 14.

Each of the embodiments shown in FIGURES 3, 6 and 7 maintains thediameter d of the center conductor 14 along the length of the connector.By holding the inner diameter of the connector bores to be substantiallythat of the inner diameter D of the cable to be connected and byproviding appropriate dielectric insert material, the effectivecharacteristic impedance of the connector may be held to be the same asthat of the cable. It is contemplated that in certain instances it maybe desirable to have the central pin members of each connector partslightly deviate from the diameter of the central conductor 14. As iswell appreciated by those skilled in the art, such deviations, makingthe diameter of the central pin members either larger or smaller thanthe central conductor, will cause discontinuities which affect theefiiciency of the connector. As is also generally appreciated, theeffective dielectric constant of an incremental length throughout theconnector can be altered to compensate for such discontinuities, or thediameter of the outer conductor bore portions of the connector may beincreased to accomplish compensation. Alternatively, some compensationmay be achieved by diameter change and further compensation achieved bychoice of dielectric constant and material. These procedures may beutilized with the connector of the invention if such is desirable due tothe particular application encountered. It is preferred, however, thatthe arrangement shown in FIGURES 3, 6 and 7 be carried out whereverpossible. As yet a further alternative, wherein application requirementsdictate deviations in conductor diameters final compensation may beachieved in the manner shown in my U.S. patent application, Serial No.276,712, filed April 30, 1963.

As a final point, the embodiments above described show examples whereinthe connector halves are joined by complementary threaded members. It isalso contemplated that the connector halves may be joined by otherstandard arrangements, including those wherein the threaded members asshown would be replaced by members without threading, but including thewell known bayonet and slot arrangement. For example, in the embodimentin FIGURES l-3, the sleeve 44 might be slotted by diagonal slots oneither side thereof and the sleeve 82 might be made to include integralpost members extending therefrom such that the slots would engage theposts to lock the halves together. As is standard in such assemblies, anadditional spring member would be utilized to hold the post memberswithin the slots.

In an actual embodiment constructed in accordance with FIGURES 1-3 forconnecting Phelps-Dodge Foamflex cable of the dimensions above given,the connector had the following approximate dimensions in thousandths ofan inch:

Sleeve bore I.D 676 Sleeve extension O.D. 736 Sleeve extension length750 9. Ring maximum I.D. 820 Ring length 1060 Ring minimum I.D 760 Ringthickness 20 Contact pin O.D 240 The sample connector was pullatested tocable destruction at approximately 1200 lbs.; the cable tensile ratingbeing 420 lbs. before cable stretch causes excessive signal degradation.The sample connector provided a VSWR below 1.10 from to 6 gh. signalfrequency.

Changes in construction will occur to those skilled in the art andvarious apparently different modifications and embodiments may be madewithout departing from the scope of the invention. The matter set forthin the foregoing description and accompanying drawings is offered by wayof illustration only. The actual scope of the invention is intended tobe defined in the following claims when viewed in their properperspective against the prior art.

I claim:

1. An improved connector for coaxial cable of the type having a centerconductor surrounded by dielectric material and an outer conductorincluding a rigid metallic outer sleeve having an extension slightlylarger in outer diameter than the inner diameter of the cable outerconductor, a locking ring of relatively thin expandable material adaptedto be fitted over the outer conductor and axially held with saidextension being forced within said ring and outer conductor to expandsuch, said locking ring having a tapered portion in its undeformed stateof an inner diameter less than the outer diameter of the portion of theouter conductor expanded by said extension such that the said lockingring is loaded by substantial and residual circumferential stressesalong said portion, said connector including within said outer sleeve acenter contact member secured to said cable center conductor with theinner diameter of the sleeve and the outer diameter of the contactmember being approximately equal to the spacing between the cable centerconductor and the cable outer conductor along the interior length of theconnector.

2. The connector of claim 1 wherein the said tapered portion of the saidlocking ring is disposed proximate the center of the length of saidlocking ring with one end of said locking ring fitted over saidextension and said cable outer conductor, and the said one end has aninner diameter larger than the expanded outer diameter of the outerconductor whereby the locking ring has a minimal residualcircumferential stress at such end.

3. The connector of claim 2 wherein the other end of said locking ringhas an inner diameter approximately that of the outer conductor of thecable, whereby the residual circumferential stress at such other end isminimal.

4. An improved connector for coaxial cable of the type having a centralconductor, a surrounding dielectric material and a surrounding outerconductor comprising in combination, intermating outer sleeve membersfor each half of the connector with means disposed on the forwardportion of each member to lock said members together, an extension ofrelatively thin rigid metal on the other end of each sleeve memberadapted to be fitted beneath the outer conductor of the cable, the saidextension having an outer diameter larger than the inner diameter of theouter conductor of the cable so as to expand said outer conductor, atapered ring member of relatively thin expandable metal adapted to befitted over said cable outer conductor and having portions of its innerdiameter in its unstressed condition less in diameter than the expandeddiameter of the outer conductor when positioned over said extension,said tapered ring member as fitted over said outer conductor and saidextension being adapted to be forced axially together to position saidextension within said outer conductor and said tapered ring member todrive the outer conductor of the cable inwardly against the extensionand lock said sleeve members to the cable through a substantial andresidual circumferential stress developed in said ring member by anoutward expansion thereof, a central connector contact for each sleevemember adapted to be secured to the central conductor of a cable halfwith the forward portion of one central contact adapted to engage theforward portion of the other central contact and both central contactshaving a maximum diameter substantially the same as that of the centralconductor of the cable.

5. An improved means for interconnecting a coaxial connector half to acoaxial cable of the type having an inner conductor surrounded bydielectric material and an outer conductor of metallic tubing, the saidmeans com prising a sleeve extension of rigid metallic constructionadapted to resist deformation, said extension having an inner diameterapproximately equal to the outer diameter of the dielectric material andan outer diameter greater than the inner diameter of the cable outerconductor, a ring member of a length greater than that of the saidextension with its smallest diameter approximating the outer diameter ofthe cable outer conductor and adapted to be fitted over the cable outerconductor, the said ring member being comprised of an expandablemetallic construction having characteristics such that said ring memberas fitted over said cable outer conductor may be axially held with saidextension being axially driven within said outer conductor and ringmember to expand such and develop a substantial residual circumferentialstress in said ring member locking said cable to said half.

6. An improved means for locking an electrical connector assembly to acoaxial cable comprising in combination a sleeve extension of rigidmetallic construction having an outer diameter larger than the innerdiameter of the cable outer conductor, a ring member adapted to befitted over the cable outer conductor with the said extension beingaxially driven relative to said ring member to expand said outerconductor and said ring member radially, the said ring member having atapered configuration prior to expansion and material characteristics ofyield strength to preclude buckling due to axial loading whereby todevelop substantial residual circumferential stresses looking the outerconductor to the said extension.

7. The means of claim 6 wherein said ring member has a material wallthickness greater at longitudinal center portions than at end portions.

8. An improved coaxial device for connecting the ends of coaxial cableof the type having an inner conductor surrounded by a dielectricmaterial and an outer conductor, including in combination a pair ofoppositely oriented sleeves of rigid metallic construction each havingan extension, a ring member for each extension of a metallicconstruction having a yield strength to prevent buckling, each ringmember being of a length greater than that of the said extension andhaving an end portion approximating in inner diameter the outer diameterof the cable outer conductor with the ring member being adapted to befitted over the cable outer diameter and with the said extension beingdriven axially relative to the said ring member as fitted over saidouter conductor whereby said outer conductor and ring member areexpanded radially to develop residual inwardly directed radial forceslocking said outer conductor to said extension and whereby said end ofsuch ring member supports said cable axially outward of said extension.

9. The device of claim 8 wherein said sleeves include an interior boreequal to the inner diameter of the cable outer conductor and each saidring member includes an inner diameter proximate the outer end of eachextension as fitted thereover to hold said outer conductor in-wardly atthe end of said extension to minimize the outer conductor deformation atsuch outer end.

(References on following page) References Cited by the Examiner UNITEDSTATES PATENTS OTHER REFERENCES AMP Incorporated Publication 4295M-C58,copy- McTighe 339'-276 i 195 V v Okress 333*97 5 Select'r'o"Sub-Miniature R.F. Connectors Catalog D 2-1, Johannesen 333-97 H k pages2 and 3.

FOREIGN PATENTS HERMAN KARL SAALBACH, Primary Examiner.

Great Britain. Germany.

1. AN IMPROVED CONNECTOR FOR COAXIAL CABLE OF THE TYPE HAVING A CENTERCONDUCTOR SURROUNDED BY DIELECTRIC MATERIAL AND AN OUTER CONDUCTORINCLUDING A RIGID METALLIC OUTER SLEEVE HAVING AN EXTENSION SLIGHTLYLARGER IN OUTER DIAMETER THAN THE INNER DIAMETER OF THE CABLE OUTERCONDUCTOR, A LOCKING RING OF RELATIVELY THIN EXPANDABLE MATERIAL ADAPTEDTO BE FITTED OVER THE OUTER CONDUCTOR AND AXIALLY HELD WITH SAIDEXTENSION BEING FORCED WITHIN SAID RING AND OUTER CONDUCTOR TO EXPANDSUCH, SAID LOCKING RING HAVING A TAPERED PORTION IN ITS UNDEFORMED STATEOF AN INNER DIAMETER LESS THAN THE OUTER DIAMETER OF THE PORTION OF THEOUTER CONDUCTOR EXPANDED BY SAID EXTENSION SUCH THAT THE SAID LOCKINGRINS IS LOADED BY SUBSTANTIAL AND RESIDUAL CIRCUMFERENTIAL STRESSESALONG SAID PORTION, SAID CONNECTOR INCLUDING WITHIN SAID OUTER SLEEVE ACENTER CONTACT MEMBER SECURED TO SAID CABLE CENTER CONDUCTOR WITH THEINNER DIAMETER OF THE SLEEVE AND THE OUTER DIAMETER OF THE CONTACTMEMBER BEING APPROXIMATELY EQUAL TO THE SPACING BETWEEN THE CABLE CENTERCONDUCTOR AND THE CABLE OUTER CONDUCTOR ALONG THE INTERIOR LENGTH OF THECONNECTOR.